My Two Cents:

1. Let’s say I’m a player with 5hrs of game time every day (a fair amount!). During this time I have to decide to dungeon, craft or level up a class...or I can dedicate it entirely to grinding for ATMA. If I’m lucky, I’ll get one every 5hrs. That means it’s going to take me roughly two weeks to earn enough ATMA for my relic (assuming I decide to dedicate my entire game time to this). That doesn't sound too bad, considering that the previous relic took 900 myth or...roughly about two weeks (900/450 cap). There is however one major difference between these two approaches.
a. Getting 900 myth involved doing one of 8 dungeons, CT, 6 different trial modes (EX/HM), Thorn or Coil. The variety kept it fresh, exciting and fun. Not to mention that there was pre-programmed downtime between each task (Queue Time) that you could use to craft, grab a soda or do some event quests. With FATE grinding, all you can do is FATE grind.